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[v2] iommu/vt-d: Disable ATS support on untrusted devices

Message ID 1553843655-21478-1-git-send-email-aaron.ma@canonical.com
State New
Headers show
Series [v2] iommu/vt-d: Disable ATS support on untrusted devices | expand

Commit Message

Aaron Ma March 29, 2019, 7:14 a.m. UTC 
From: Lu Baolu <baolu.lu@linux.intel.com>

BugLink: https://bugs.launchpad.net/bugs/1820153

Commit fb58fdcd295b9 ("iommu/vt-d: Do not enable ATS for untrusted
devices") disables ATS support on the devices which have been marked
as untrusted. Unfortunately this is not enough to fix the DMA attack
vulnerabiltiies because IOMMU driver allows translated requests as
long as a device advertises the ATS capability. Hence a malicious
peripheral device could use this to bypass IOMMU.

This disables the ATS support on untrusted devices by clearing the
internal per-device ATS mark. As the result, IOMMU driver will block
any translated requests from any device marked as untrusted.

Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Suggested-by: Kevin Tian <kevin.tian@intel.com>
Suggested-by: Ashok Raj <ashok.raj@intel.com>
Fixes: fb58fdcd295b9 ("iommu/vt-d: Do not enable ATS for untrusted devices")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/iommu/intel-iommu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Aaron Ma March 29, 2019, 7:23 a.m. UTC | #1 
Sorry, missed cherry-pick info.

Please ignore this one.

Thanks,
Aaron
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Patch

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 1c72434af56d..5ade9ac6d3e8 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2518,7 +2518,8 @@  static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
 	if (dev && dev_is_pci(dev)) {
 		struct pci_dev *pdev = to_pci_dev(info->dev);
 
-		if (!pci_ats_disabled() &&
+		if (!pdev->untrusted &&
+		    !pci_ats_disabled() &&
 		    ecap_dev_iotlb_support(iommu->ecap) &&
 		    pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ATS) &&
 		    dmar_find_matched_atsr_unit(pdev))